This proposal is divided into three sections, each designed to further elucidate the epidemiology of peptic ulcer disease: Section one - Dyspepsia negative to all tests and duodenal ulcer. Three samples will be drawn from patients from the Wadsworth V.A. clinics: 100 men with duodenal ulcer; 100 men with dyspepsia negative to all tests; and 100 control men without any history of ulcer disease matched to the duodenal ulcer cases on the basis of age and race. Risk profiles, based on medical, psycho-social and biochemical variables, will be developed for each of these groups. The dyspeptics negative to all tests will be compared with the duodenal ulcer cases and the controls to determine if this group, or a subset, can be considered as representing a pre-ulcer population. Section two - Complications of peptic ulcer. One hundred men with a history within the past year of complications of peptic ulcer will be matched by age, race and duration of ulcer symptomatology to male ulcer patients with no history of complications. Risk profiles, similar to those described above, will be developed for each group. Efforts will be made to determine whether such a profile can help identify ulcer patients at high risk for future complications. Section three - Through a subcontract, investigate the interaction of genetic and environmental factors in peptic ulcer. First degree relatives of the subjects in the above sections will be studied in an attempt to evaluate the interaction of specific environmental factors with specific genetic forms of the spectrum of peptic ulcer disease.